Daniel Barth, Nicholas W. Papageorge, Kevin Thom
Journal of Political Economy, 2020, vol. 128, No.4
Barth, Papageorge, and Thom (2020)
.
└── Chromosome
└── DNA
└── Gene
└── Genome
Twin studies
Genome wide association studies (GWASs)
Regress outcome \(Y_{i}\) on each SNP using \(J\) estimating equations:
\[ Y_{i}=\bfmu'\bfx_{i}+\beta_{j}SNP_{ij}+\epsilon_{ij}, \quad j=1,\dots,J. \]
Polygenic score of \(i\) for the outcome \(Y\) = “Educational attainment (EA) score”
\[ PGS_{i}=\sum_{j=1}^{J}\tilde{\beta} SNP_{ij} \]
Use Bayesian LDpred procedure to correct for correlations in \(\tilde{\beta}_{j}\)
Use all SNPs: Better out-of-sample results than using only SNPs with genome-wide significance \(p\) value \(< 5*10^{-8} =\) .0000005%
PGS is considered to be a predictor of individual fixed effects
2590 HHs, 5701 HH-year observations (Table 1)
our sample comprises households for whom wealth data are most likely to be both accurate and comprehensive.
However, the magnitudes of these differences are similar and relatively modest across alternate samples. Restricting our sample to retired households balances concerns about sample selection and measurement error. (p.19)
Meaning:
Fig 2A
EA score \(\propto\) wealth
Table 2 also shows EA score \(\propto\) wealth ($475K, q4-q1), lifetime labor income ($380K, q4-q1)
Fig 2B
EA score \(\propto\) wealth similar between high schoolers vs college grads, up to q3
Tab 4
EA score \(\propto\) wealth gradient: .246 (raw)→.070 (+edu)→.047 (+labor income)
Gradient: “ability” + school quality ← income measure error
Robust to:
EA score ↑